Search results for "System model"

Global distributions of diazotrophs abundance, biomass and nitrogen fixation rates - Gridded data product (NetCDF) - Contribution to the MAREDAT Worl…

2012

The MAREDAT atlas covers 11 types of plankton, ranging in size from bacteria to jellyfish. Together, these plankton groups determine the health and productivity of the global ocean and play a vital role in the global carbon cycle. Working within a uniform and consistent spatial and depth grid (map) of the global ocean, the researchers compiled thousands and tens of thousands of data points to identify regions of plankton abundance and scarcity as well as areas of data abundance and scarcity. At many of the grid points, the MAREDAT team accomplished the difficult conversion from abundance (numbers of organisms) to biomass (carbon mass of organisms). The MAREDAT atlas provides an unprecedente…

Predicting future thermal habitat suitability of competing native and invasive fish species: From metabolic scope to oceanographic modelling

2015

Global increase in sea temperatures has been suggested to facilitate the incoming and spread of tropical invaders. Here, we determined the effect of temperature on the aerobic metabolic scope of two competing fish species, one native and one invasive, and we predicted their future thermal habitat suitability.

Translating the Global Script of the Sustainable University: The Case of the University of Oslo

2015

In this chapter, Translating the Global Script of the Sustainable University: The Case of the University of Oslo, Romulo Pinheiro, Maryam Faghihimani and Jarle Trondal discuss the green strategy of University of Oslo. This chapter, which is conceptually based on neo-institutional theory, approaches the notion of the ‘sustainable organisation’ as a global, legitimate script, i.e. a dominant hegemonic idea which, once adopted and consequently adapted locally, is likely to enhance both internal and external legitimacy. This analysis is built on the empirical case of the University of Oslo (UiO), that sheds light on the ways in which the notion of a ‘sustainable university’ has been locally ‘tr…

Analysis of Offshore Knuckle Boom Crane - Part One: Modeling and Parameter Identification

2013

This paper presents an extensive model of a knuckle boom crane used for pipe handling on offshore drilling rigs. The mechanical system is modeled as a multi-body system and includes the structural flexibility and damping. The motion control system model includes the main components of the crane's electro-hydraulic actuation system. For this a novel black-box model for counterbalance valves is presented, which uses two different pressure ratios to compute the flow through the valve. Experimental data and parameter identification, based on both numerical optimization and manual tuning, are used to verify the crane model. The demonstrated modeling and parameter identification techniques target…

Cybernetics of Value Cocreation for Product Development

2016

PEM Fuel Cell System Model Predictive Control and real-time operation on a power emulator

2010

Fuel Cell Systems (FCS) seem to be among the most reliable devices to produce clean energy, although they still suffer for many problems, mostly related to the fragility of the Polymer Electrolyte Membrane (PEM). Particularly, this paper focuses on the oxygen starvation, that leads both a decrease of the FCS performance and a shortening in the FCS lifetime. The purpose is to use the Model Predictive Control (MPC) and its capacity of accounting for linear constraints for managing the air system without risking to damage the fuel cell. Two control inputs and no static feed-forward actions have been used. Results show that the MPC is able to avoid the oxygen starvation, even with a sudden incr…

Once t hrough m ultistage fl ash d esalination: gPROMS d ynamic and s teady s tate m odeling

2010

This study focuses on modeling the steady state and dynamic behavior of the multistage flash desalination process (MSF) using gPROMS. This modeling tool allows for simultaneous coding of the system dynamics and steady state performance. In addition, it allows the use of the most efficient solvers for a set of non-linear differential and algebraic equations describing the MSF process. The system model and analysis are based on actual plant data that includes 21 flashing stages and a capacity of 378 kg/s (32,000 m3/d). The simulated unit is part of a massive MSF installation in Doha, Kuwait. System's dynamic behavior is simulated by a step change in the input values of the main operating para…

Decoding the Japanese Lean Production System according to a Viable Systems Perspective

2012

The increase in the complexity and variability of the business environment, due to constant and rapid changes in markets, calls for more flexible and effective production systems. Of the most valuable production systems, the Japanese lean production system (LPS) is the best known and studied, but is still not the most widely applied with success outside Japan. The reason for the low level of success of lean production outside its native country is the lack of understanding of the strong interactions which hold between enterprises and business systems. In order to fill this gap in our knowledge, we investigate the systemic interactions according to the Viable System View. To develop our anal…

An automatic tool for reconstructing monthly time-series of hydro-climatic variables at ungauged basins

2017

Abstract Integrative information models for filling/reconstructing hydro-climatic time-series are required for a variety of practical applications. A GIS-based model for a rapid and reliable assessment of monthly time-series of several key hydro-climatic variables at the basin scale, is here developed as plug-in and applied to the entire region of Sicily (Italy). The plug-in, once the desired basin outlet section and time-window are selected, uses appropriate spatial techniques and algorithms to identify its drainage area and estimate the corresponding mean areal rainfall and temperatures time-series. A recent regional regressive rainfall-runoff model is successively applied for the assessm…

Perceptually Optimized Image Rendering

2017

We develop a framework for rendering photographic images by directly optimizing their perceptual similarity to the original visual scene. Specifically, over the set of all images that can be rendered on a given display, we minimize the normalized Laplacian pyramid distance (NLPD), a measure of perceptual dissimilarity that is derived from a simple model of the early stages of the human visual system. When rendering images acquired with a higher dynamic range than that of the display, we find that the optimization boosts the contrast of low-contrast features without introducing significant artifacts, yielding results of comparable visual quality to current state-of-the-art methods, but witho…